Interface-modulated deformability of liquid metal bridge

Bridging liquid metal (LM) droplets embedded in composite matrices, such as elastomer polymers, are crucial for maintaining high conductivity and mechanical stretchability in flexible electronics. However, the deformability of these LM bridges under strain remains poorly understood. Here, we combine in situ transmission electron microscopy experiments with theoretical modeling to investigate the effects of interface modulation on LM bridge deformability. We find that strong interfacial wettability between LM nanodroplets and the solid substrate enhances stretchability, while the surface oxide layer of LM nanodroplets plays a more complex role. A thin oxide layer promotes symmetric liquid bridge formation, whereas a slight increase in thickness induces super-stretched liquid bridges. However, excessive oxide growth suppresses deformability by reducing LM liquidity. Accordingly, a strategy for controlling the deformation was developed by modulating the thickness of oxides through the regulation of stretching duration. This study reveals the kinetics of interface-driven liquid bridge deformation, providing fundamental insights for the precise engineering of stretchable LM-based conductors in next-generation flexible electronics.